Back panel of a case for an electronic device



FIG. 1 is a perspective view of a back panel of a case for an electronic device showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a right side elevational view thereof.

Portions shown in broken lines are for illustrative purpose only and form no part of the claimed design. 

CLAIM The ornamental design for a back panel of a case for an electronic device, substantially as shown and described. 